Congratulations! We are in the same boat and chose to run the same hallway tile into the powder room but are going different in the Master and Kids' bath. They are on a different floor though and hardwood upstairs.
I think you have to look at the overall size of the house and try and minimize the number of different floor types if it isn't that big.

Picking the tile for the house is easy but what has me going crazy is the master bath. I dont know what to run on the floor and what tiles to put in the shower. One thing is looking at magazines but being in the tile place is another story. I wish someone cold just tell me what will look good and I'll just buy it.

Just me, but one of my personal pet peeves is bathrooms and kitchens that match in any way. My house used to have the same salito colored tiles in the kitchen and both bathrooms. They were a different size, but I still found it unsettling. They are gone in the kitchen already and soon will be gone in the bathrooms.

I recently toured a very expensive home and they'd used the same white granite w/ blue streaks in the kitchen and the bathroom. It was beautiful and used with different tiles, but I still did not want to see the same counter in the kitchen as I just saw next to the toilet.

"I wish someone will just tell me what will look good and I'll buy it"

OK I'll take you up on that :) First, having the same tile appear in a house off and on is one thing...having it all be the same (if it's not a tiny home) is a bit "builder basic" even if it's lovely travertine.

I'd mix it up a bit. Go lux in your master bath by doing the floor in a dark empredor marble with accents of your travertine something like this:

The color might be more true here...it's a chocolate color:

marble is great for a master bath. Luxurious and rich and it's not going to get the beating in there it would in a main room. An added bonus is that dark empredor is pretty inexpensive as well.

In another room you can accent with something else...for instance, your tile (similar) with nordic black antique granite: (not grouted yet, just wanted to show the mix)

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Same room with walls to show how different it looks from the other rooms, but it's the same tile as the base of the floor:

Then you could go goofy wild :) Same tile with crocodile porceline tile accents:

Accent tiles really shake the "same tile everywhere" look up well. All of those rooms have the same tan travertine, and yet look very different. Did that give you any ideas?

I'm in agreement about the kitchen and bath never having the same floor. My kitchen is 360degrees from the bathrooms for the same reason noted above...it just does not feel right.

We have the same tile (16" ligh saltillo imitation) through the whole haouse except for the baths, which have a smaller different color tile. The tile guy made a /\/\/\/\/\ border design at the entry to the baths with the house tile and the bath tiles to make a transition. It looks good.

I think if you find something you really love then you will like it, there are plenty of things you can do in the bathrooms that are different with wall tiles, accents, sinks and such. The travertine is a beautiful look, my entire downstairs is marble. It is a very open design and I would hate it if it were chopped up. I think it is a beautiful look and will go with everything and allow you to do what ever you want elsewhere.

frankly having different color tile from one room to another makes me think sale-shopper...
we took up kitchen and utility room tile in house we are getting ready for the market just so the tile throughout would be uniform--taking up was not so costly because it popped up easily but the larger amount of time just about doubled that part of the budget--it is a fairly basic beige-type travertine look tile in 20 x 20...putting smaller tiles in upstairs bar area and half bath...

in my area--DFW TX--using the same flooring/carpet/tile is just the way things are done--no matter how expensive the house--even 1MM and up most of the time...
this one has some accent pieces of the stone used in master bath in the floor but basically it is same travertine (I guess) where area is tiled...
The one part that I think really does not work in this house is the back splash behind the stove--that is basically a cop-out--actually pretty cheap compared to other aspects of the choices used...

I think have variety from room to room is something that might be more common back east from what I have seen on some of the design/home shows...where people tend to address a room individually vs as part of the whole floorplan...
we are going with the same carpet when we pick that as well...
but I like harmony vs contrast most of the time...

Here is a link that might be useful: Colleyville builder spec